The fallout from last week's elbow incident at Levante has Ronaldo even considering his future at Real.
Karanka said: "The coach already said the other day in the press room that there are questions that don’t deserve answers.
"The images of the match against Levante are there for all to see and there is no need to dwell on what happened. Anyone who knows Cristiano Ronaldo knows that he has to be really bad to not be out on the field. Tomorrow he will give everything for this team, as he always does".